Four is a crucial number in football. Players raise four fingers at the start of the fourth quarter. There are four downs. Most defenses have a front four. Notre Dame had the Four Horsemen.

Now, here we are at Week 4 of this season, which is crucial for four teams.

Boise State, which faces Oregon State of the Pac-10, is seeking its fourth consecutive victory over a "Big Six" opponent, and the Broncos know that the Beavers are the last real obstacle to an unbeaten season.

South Carolina seeks its first 4-0 start since 2001, and that will require winning at Auburn, which has won all four SEC games it has played against the Gamecocks.

West Virginia is looking to gain some respect for itself and the Big East as it whole as it travels to LSU. The Mountaineers are 3-0 and trying to go to 4-0 for the first time since 2007.

Arkansas is hoping to avoid a fourth consecutive loss to Alabama. The Tide won by -- what else? -- four touchdowns last season.

Georgia is 0-2 in SEC play for the first time in Richt's 10-year tenure. That puts the Bulldogs in a must-win situation Saturday at Mississippi State. This is more about Richt's job security than Georgia's faint SEC title hopes. It's tough to imagine Georgia getting back in SEC contention even if it wins Saturday, but it's easy to envision how a loss in Starkville could put even more heat on Richt. Georgia should be able to win, but WR A.J. Green's absence and MSU's defense make this a dangerous game.

Best game: Alabama at Arkansas, 3:30 p.m., CBS. Throughout the offseason, Arkansas was billed as a threat in the SEC West. Now comes the time to prove it. Ryan Mallett and the Hogs' receivers will be the greatest challenge the Tide's rebuilt defense has faced thus far. Of course, Alabama RBs Mark Ingram and Trent Richardson form a one-two punch that the Razorbacks must stop.

Don't overlook these: N.C. State at Georgia Tech (noon, ESPN) and Virginia Tech at Boston College (noon, ACC syndication). At least the ACC's widespread struggles make the race for the conference championship a little more interesting. Virginia Tech, Miami, Georgia Tech, North Carolina and Florida State were ranked in the preseason coaches' poll, but only Miami remains. Meanwhile, NC State and Boston College were nowhere to be found in the polls, but they're the only remaining undefeated ACC teams. They might be contenders in the Atlantic, but they'll need strong showings against Coastal Division teams this week to prove it.

On the midweek marquee: Miami at Pittsburgh, Thursday, 7:30 p.m., ESPN. The winner of this game will get a confidence boost heading into October while the loser will fall to 0-2 against FBS teams. Miami QB Jacory Harris is looking to recover from his four-interception game at Ohio State, while Pittsburgh will try to find a pass rush without injured DE Greg Romeus. The sideline matchup also will be intriguing: Pitt's Dave Wannstedt was Randy Shannon's defensive coordinator as a player at Miami and in the NFL.

Player under the gun: Pittsburgh DE Brandon Lindsey. Pitt led the nation in sacks last season, but the Panthers could struggle to maintain that kind of pass rush now that star E Greg Romeus will miss a significant portion of the season as he recovers from back surgery. That puts quite a burden on Lindsey, who will replace Romeus in the lineup. Lindsey had two sacks against New Hampshire, but what can he do against better opposition? We'll find out Thursday when Pitt hosts Miami, which has some offensive line issues.

Best coordinator chess match: Arkansas coach Bobby Petrino vs. Alabama defensive coordinator Kirby Smart. Petrino calls the plays for Arkansas, and he needs to be sharp if his Hogs are to have any shot at the upset of the Tide. Arkansas' defense is not going to be able to hold up against the Tide's rushing attack, so Petrino's offense is going to have to score at least in the high 20s. Smart knows his secondary will be under siege, so expect a variety of blitzes in an effort to get to Hogs QB Ryan Mallett, who isn't the most mobile guy.

BCS-buster watch: Oregon State at Boise State, 8 p.m., ABC. Well, this is it -- the Broncos' last big hurdle to an unbeaten season. But how good are the Beavers? They have the ninth-ranked defense and the last-place offense in the Pac-10. Still, coach Mike Riley will have his team motivated and ready for the chance to stick a fork in the Broncos' BCS title-game hopes.

Best individual matchup of the week: Pittsburgh WR Jonathan Baldwin vs. Miami CB Brandon Harris. Baldwin is one of the nation's most talented receivers, but Pitt QB Tino Sunseri is a first-year starter and hasn't been asked to throw much. That needs to change, as good opponents will be able to bottle up the rushing attack without the threat of a pass. Look for Harris to spend some time guarding Baldwin. Baldwin has a 6-inch height advantage, but Harris is a scrappy guy who gets his hands on a lot of balls.

Best unit matchup of the week: Oregon offensive line vs. Arizona State front seven. Oregon's offensive line has played at a high level thus far, opening cavern-like holes for the Ducks' running backs. They will get one of their biggest tests against a mean and nasty Arizona State front seven. DT Lawrence Guy and LB Vontaze Burfict are the stars. Wisconsin ran effectively on the Sun Devils in a one-point victory last week, and the only offensive line in the nation that is better than Oregon's is Wisconsin's.

Injury report Auburn lost right offensive tackle A.J. Greene for the season with a left ankle injury suffered in the Tigers' 27-24 overtime victory against Clemson on Saturday night. Sophomore John Sullen will take over. Sullen's first task will be formidable, as Auburn plays host to a South Carolina defense that ranks first in the SEC against the run (59.7 ypg). For Auburn to win, it must run. Is Sullen up to the task?

Record watchWith Saturday's 30-16 victory over Connecticut, Temple is 3-0 for the first time since 1979. If the Owls are going to win their first four games for the first time since 1974, they will need to find a way to beat Penn State. When the Owls last beat Penn State, in 1941, Joe Paterno was in junior high. Since that win in '41, the Owls are 0-34-1 against the Nittany Lions. RB Bernard Pierce should help Temple have at least a respectable showing. The Owls have been outscored 154-9 in the past four meetings with the Nittany Lions.

Coaching connection:Rutgers' Greg Schiano vs. North Carolina's Butch Davis. Here's another coaching matchup with Miami ties. Schiano was Davis' defensive coordinator with the Hurricanes in 1999 and 2000. The 2000 Miami team went 11-1 and finished the season ranked No. 2. Miami won the 2001 national championship without either coach. Schiano took the Rutgers job two months before the Cleveland Browns hired Davis away from UM, which led to Miami promoting Larry Coker to coach. Davis and North Carolina beat Schiano and Rutgers 44-12 in their first meeting, in 2008.